Papers by Author: Yi Hui Yin

Abstract: Precise simulation of the temperature distribution throughout welding process is basic for stress analysis. In this paper, numerical simulations and multi-factor regression were used to investigate how the three process parameters, laser power, spot radius and spot offset, influence the temperature distribution in Beryllium (Be) cylindrical shells. The experiments are designed by the compound response surface method. Based on numerical results, regression model are gained as an expression about laser power, laser spot radius and laser spot offset. Then the effects of these three parameters on temperature distribution were obtained. The results could provide guidelines for welding process of Be cylindrical shells.

Abstract: The effect of geometric clearances on the stress and deformation distributions of a wedged-ring joint structure is studied, five cases of dimensional tolerance of each contact surface, i.e., the maximum, minimum, mean of maximum and minimum, mean of maximum and mean, and mean of minimum and mean are investigated, and the probable states that the wedged-rings attach with the upper cylinder or attach with the lower cylinder radially in the assembly process are considered as well. The results of finite element numerical simulations indicate that in the design tolerance zone, the effects of geometric clearances between contact surfaces on the displacement and stress distributions of the structural components are weak. Only when the wedged-rings attach tightly with the upper cylinder or with the lower cylinder, the displacement and stress distributions in the joint of the structure occur a dramatic variation, and the assembly processing measure making the wedged-rings attaching tightly with the lower cylinder can be adopted to effectively decrease the stresses and deformations in the joint of the structure.

Abstract: In this paper, the formulas of elasto-plastic deformation and stresses of a multilayer pressure vessel were deduced in consideration of the linear hardening elasto-plasticity of the material, and the relations between plastic zone and interior pressure and between equivalent stress and interior pressure were obtained for a monolayer vessel. Then, treating the strength problem of a pressure vessel with a fuzzy or random one and based on the principle of the information entropy theory that the information of a variable does not change with its expressed type, the fuzzy variables in the problem were transformed into random ones or the random variables into fuzzy ones. At last, the strength reliability degree of the pressure vessel was solved out by use of the random reliability method and the fuzzy one, respectively. The relative error between the fuzzy and random reliability degrees is 4.08% and the fuzzy reliability degree is closer to the determined one than the random one.